The present invention is based on a method of controlling a sliding roof.
A method of electronic monitoring of an adjusting drive arranged in a motor vehicle, in particular a sliding roof drive, is known from German Published Patent Application No. 196 15 123, where a measured quantity detected by a sensor in closing the roof is compared with a threshold value for the closing force limiter for the purpose of guaranteeing, pinch protection, and when the threshold value is reached, the drive motor is turned off and/or reversed. Reaching, the threshold value thus represents a pinch criterion and leads to release of the object, such as an arm or neck, pinched between the adjusting part and a stop of the adjusting part.
In addition, the threshold value is adapted to the speed-dependent force and pressure conditions on the adjusting part, i.e., the sliding roof cover, in that the vehicle velocity is analyzed by using a tachometer signal sent to the adjusting drive. This prevents unwanted triggering of the closing, force limiter, i.e., the pinch protection, because of the forces occurring on the adjusting part at high speeds without there being an actual pinch situation. Consequently, threshold values can be adjusted as a function of speed.
However, this does not detect acceleration of the vehicle, e.g., full braking. The closing of a sliding, roof takes place more easily in negatively accelerated systems than in unaccelerated systems. This leads to the problem that the positive acceleration of the sliding roof cover in the closing direction caused by a negative acceleration of the vehicle during the closing operation of a sliding roof and consequently also the related increase in rotational speed of the drive motor are not detected. A subsequent reduction in acceleration, in particular due to stopping the vehicle, leads to a reduction in rotational speed of the sliding roof motor. This reduction in rotational speed is interpreted as a pinch criterion, so the pinch protection responds and the sliding roof is stopped and/or reversed in an unwanted manner.
The method according to the present invention has the advantage that braking of a vehicle is detected by a controller of the sliding roof device, and the pinch protection, i.e., the closing force limiter, is corrected so that faulty reversal of the sliding roof is suppressed when the vehicle is decelerating or stops in particular while the roof is closing.
It is especially advantageous that the controller determines from the input signals at least one acceleration value of the vehicle and compares this value with a limit value. Reaching the limit value is interpreted as full braking of the vehicle and leads to correction of the pinch protection. This correction of the pinch protection is reversed by the controller after braking.
The method is improved because not only one acceleration value is used but instead a plurality of acceleration values is used, preferably two, each of which is compared with a predetermined limit value. On reaching both limit values, full braking of the vehicle is then deduced and the pinch protection is corrected.
Preferably the acceleration values are obtained from a speed signal in particular a tachometer signal which is sent to the controller. The tachometer signals are stored temporarily in succession in a ring memory. The acceleration values are determined by forming the difference in an electronic analyzer.
The determination of a pinch situation is based, for example, on a determination of the rotational speed of a motor armature shaft and a comparison of the rotational speed with a threshold value for the closing force limiter, so that a correction of the pinch protection is performed by correcting the threshold value, preferably increasing it.